Technical Field
The present invention relates to semiconductor processing, and more particularly to devices and methods for device fabrication, which employ directionally formed nitride to protect layers during processing.
Description of the Related Art
During device fabrication, previously formed structures may be at risk of damage due to subsequent processing. In one example, buried oxide (BOX) layers and shallow trench isolation (STI) regions formed in or on a substrate may be damaged by one or more preclean processes. The preclean processes may be needed to provide a clean silicon interface to start epitaxial deposition, e.g., on semiconductor fin structures employed to form fin field effect transistors. Such a preclean process consumes oxide of one or more of the BOX for a silicon-on-insulator substrate case or STI for bulk substrate case. The consumption of oxide or oxide gouging can cause subsequent process integration issues.